Such filtering assemblies consist of a filter body inside of which a filtering cartridge is arranged, which generally has a cylindrical shape and which includes a filtration medium, which can be made for example of paper, cardboard or a felt. This filtration medium is conventionally defined by two end flanges.
Such filtration cartridges generally cooperate with a central tube, secured or not to the flanges, of which the external diameter is adjacent to the internal diameter of the filtration medium so as to limit deformations of the medium due to the pressure exerted inside the filtration assembly.
The lower flanges can be extended so as to have means for installing and holding the cartridge in the filtering assembly. Alternatively, filtration assemblies implementing a tube on which the filtration cartridge is attached are known, in which the tube is permanently mounted in the filtering assembly.
When the cartridge placed in the tank is used up, i.e. when the filtering element no longer performs its role of satisfactory filtration, the used cartridge of the tank is removed and replaced by a new cartridge. In this change, the operator must extract the cartridge from the tank of the filtering assembly in order to be capable of inserting a new cartridge therein.
According to an approach in which the lifting of the filtering assembly lid leads to extraction of the cartridge, a classic solution consists of integrating a support tube in the lid, with the cartridge being held on the support tube by means of a felt seal.
Handling of these filtering assemblies is not easy in practice.
Moreover, to replace the cartridge, the operator must grab the used cartridge by hand in order to separate it from the tank and/or from its support tube. Aside from the unpleasant sensation that this causes, the operator's hands quickly become stained with fluids of which the harmlessness cannot be guaranteed (in particular when they contain heavy metals).
To facilitate the extraction of used cartridges, various solutions have been proposed.
In particular, according to document DE 197 16 085 a filtering assembly is known which is equipped with a lid that cooperates by clipping with the filtration cartridge so that the removal of the lid leads to extraction of the filtration cartridge. The operator then separates the cartridge from the lid by means of any tool, attaches a new cartridge on the lid and replaces the assembly on the tank. The advantage of this solution lies essentially in the fact that, during any intervention, the operator is not forced to directly grab the filtration cartridge and therefore avoids contact with the liquid.
This type of solution, however, applies in a limited manner to tank/lid-type filtering assemblies, i.e. to filtering assemblies in which the circulation of liquid is organized by means of the tank.
In such filtering assemblies, the tank is connected to liquid inlet and outlet conduits and, consequently, is mounted securely on the conduits. In other terms, the filtration cartridge is renewed by removing the lid (which is not coupled to stationary members of its environment other than the tank itself), which, once removed, provides access to the cartridge.
According to another type of arrangement of filtering assemblies, the latter include a head/body assembly in which it is the head (generally a smelted work piece) that is connected to liquid inlet and outlet conduits, and the circulation of liquid is therefore organized by means of this head. In this configuration, once the filtering assembly has been mounted on the conduits, the head is stationary with respect to its environment and the filtration cartridge is renewed by removing the body (for example, by unscrewing it from the head).
However, for this type of configuration, the problem of handling the cartridge during renewal thereof again arises, and this problem cannot be solved with the existing solutions of “tank/lid” assemblies.
Also, a solution has been proposed by document US 2004 159600, which describes a filtering assembly including a head/body assembly in which it is the head that is connected to liquid inlet and outlet conduits, and the circulation of liquid is therefore organized by means of said head. According to this type of assembly, the head is stationary with respect to its environment and the filtration cartridge is renewed by removing the body, by unscrewing it from the head.
The objective of the solution described by this document is to enable the filtration cartridge to be installed on the head while it is coupled to the body (so as to form a single piece therewith), as well as to enable the separation thereof from the cartridge via the head, while it is also coupled to said body (again forming a single piece therewith).
Therefore, the solution described consists of implementing a ring secured to the body (either by bonding or by being made in one piece with the body by molding).
This ring has:                two studs each having a support surface, between which the upper flange of the cartridge is intended to be supported;        teeth having groove intended to receive an angular portion of the upper flange of the cartridge.        
Thus, before the cartridge is mounted in the filtering assembly, the body equipped with the ring is mounted on the cartridge, by passing the cartridge through the ring, with the upper flange being introduced into the groove of the teeth, then supported on the support surfaces of the lugs, and the cartridge is then coupled to the ring and, consequently, to the body supporting the ring.
The detachment of the cartridge from the body is performed in the reverse manner: once the body has been removed from the head, the cartridge must be misaligned with respect to the axis of revolution of the ring, in order to separate the upper flange from the support surfaces of the lugs, and then to disengage the flange from the groove.
This technique however has a disadvantage.
Indeed, the cooperation of the cartridge with the head involves only the engagement of an extension of the upper flange in a corresponding conduit of the head, with one or more seals being attached to this extension of the flange.
However, at the end of unscrewing of the body from the head, it is not ruled out that, under the effect of gravity, the extension of the upper flange of the cartridge could be disengaged from the head, at a time when the operator relaxes his or her grip on the body, thereby causing the cartridge to fall with the body, involving a risk of soiling the filtering environment with drainage of the fluid remaining in the body.